From the prairie vole to The Bachelor, the science behind love

Remarkably, the 20th season of The Bachelor is currently underway. The storyline today is as utterly predictable as it was by the third iteration: the bachelor will fall in love, or something resembling love, and with more than one woman. The question is always: who will he choose?

Presumably, it is the journey and not the outcome that hooks viewers. We’re drawn to the drama as it unfolds. We never know what happens off-camera or how much of the show is “real,” but season after season, The Bachelor, like other long-running reality TV shows, provides us with insight into repeatable human behavior.

Pair bonds—what are they?

Pair bonding is the biological term for what, in our day-to-day lives, we might call romance. It refers to two individuals with a strong mutual affinity for one another, leading to an exclusive short- or long-term commitment. In nature, pair bonding generally leads to mating and reproduction and, in some species, to a lifelong pairing. But pair bonds can also be platonic, between mothers and children or between friends and relatives.

While the term “pair bond” may not be familiar, chances are good that we’ve all experienced or are part of one. Among the relationships we form throughout the course of our lives, pair bonds are the ones that stand out. They shine a little brighter. They feel cosmic and awe-inspiring. They lift you.

And they should, after all, because these are the bonds that change our lives—if not forever, then at least for a memorable period of time.

Less than the alignment of stars, romantic love is largely the result of the mechanical underpinnings of our minds and bodies.

Scientifically, what makes a pair bond aren’t the feelings of buoyancy, yearning, and elation. Instead, the emotions we recognize as feelings of love are the result of hormones releasing from the brain into the bloodstream at specified times. Less than the alignment of stars, romantic love is largely the result of the mechanical underpinnings of our minds and bodies. Even platonic, or “social” pair bonds are based in chemistry and aided by what’s happening around us.

Everything we’ve learned from prairie voles

Humans are a species that form relationships of every kind and of every duration. That is fairly common in nature. What is less common, are the many relationships we have that do not lead to babies. Only five percent of mammals exhibit a similar social structure, and among these are voles, more commonly known as field mice.

Scientists study voles to understand social constructs like monogamy, but they also study voles to understand conditions like autism, where these social bonds fail to form.

Kristina Garfinkel, a software engineer who once studied pair bonding in voles at U.C. Berkeley, explained, “The formation of relationships are something we experience on a daily basis and are also the most profound parts of our life. The more we know about how these bonds are formed, the more we also know about why these bonds are not formed.”

By testing partner preference in controlled environments, scientists can begin to measure the hormones released when certain environmental factors or social behaviors are present or absent. In a study published by Larry J. Young, Ph.D., a professor at Emory University School of Medicine, it became apparent that “both the quality and quantity of social interactions between a pair of prairie voles contribute to the likelihood of partner preference formation”—and that sex then strengthens the pair bond.

Not surprising, right? Studies have confirmed that neurochemicals such as oxytocin, vasopressin, and dopamine play a major role in how and whether we connect. For example, in some studies, voles formed a pair bond simply by cohabitating for a period of time. In others, the cohabitation failed to form a pair bond until the voles mated.

If anything, what voles have taught us so far, is that relationships are complicated. If, for example, pair bonding does not occur, it doesn’t always mean that the necessary hormones aren’t present. It might just be that they don’t release at the right times–during mating or other “social stimulation.” Or perhaps they release but don’t travel down the neural highway that leads to bonding. Our ability to form attachments is tied to our reward circuitry. This is why love is sometimes referred to as an addiction, because it produces the same pleasurable rushes of dopamine as drugs like cocaine, in the same part of the brain.

So what’s love got to do with it?

Science tells us that a pair bond either forms or doesn’t based on our individual chemistries. And if the feelings you have for someone aren’t returned, it’s more than likely that they’re literally just not feeling it. (And probably won’t.) Thanks to science, love sounds pretty cut and dry.

Lust gets you looking around at potential partners, while romantic love helps you focus on just one person at a time.

Similar to what Young reported with the prairie voles, Fisher explains that many elements play into attraction and hormone release: timing, proximity, and mystery, for example. Mystery, Fisher says, elevates dopamine in the brain, as does doing something novel together—like helicoptering over a volcano. The producers of The Bachelor surely must know this.

As Fisher explains it, and where things get more crazy-making, is that the three brain systems leading to lust, love, and attachment can be connected, but aren’t always. “You can feel deep attachment to a long-term partner while you feel intense romantic love for somebody else while you feel the sex drive for people unrelated to these other partners,” Fisher says. “In short, we’re capable of loving more than one person at a time.”

So when it happens to the bachelor or bachelorette, know that there’s legit science behind the drama. (Some of the drama, anyway.) Similarly, be assured that biology also drives the feelings we have in our own off-screen lives. Still, what we all have in common is the big decision: which relationships we will act on, and who in the end will we choose?

Suzanne Barnecut is a content marketer for Zendesk and a frequent contributor to Relate. She is fascinated by technology, but a diehard reader of paper-made books and sender of snail mail. Find her on Twitter:@elisesuz.